Abstract: A device for pumping a liquid or gaseous current medium has a casing designed to guide the flow of the current medium and a rotary bearing motor driven rotor wheel designed to pump the current medium through the casing. The rotor wheel is equipped with a number of blades mounted on a shaft or other machine part whose function resembles that of a shaft, the blades being installed one behind the other in series in the direction of circulation. The blades project almost radially outwards in one embodiment and extend over the axial length of the rotor wheel in another embodiment. A partition fitted to the rotor wheel separates the volume flow of the medium pumped through the casing into an incoming pumping medium current, e.g. the inlet air or external air current, and an outgoing pumping medium current, e.g. the expelled air or outgoing air current. At least one heat pipe is fitted permanently to each blade, and rotates with its respective blade.